Carburetor



2 Sept. 25, w. E. ARMSTRONG 1,974,733

CARBURETOR Filed May 12. 1932 2 Sheets-Sheet 1 INVENTQR Werner Eflrmtrorzg.

BY Q. I

ATTORNEY Sept. 25, 1934", w EARMSTRGNG 1,974,733

CARBURETOR Fil'ed May 12, 1932 2 Sheets-Sf1eet 2 INVENTOR War-m1" flrr rzsrror zg.

ATTORNEY Patented Sept. 25 1934 v umrso srarss Parent. OFFICE 1,974,131? o anURET'oR Werner E. Armstrong, Milwaukee; Wis, assignor to Briggs a stratton- Corporation; Milwaukee; Wis a; corporation: of Delaware application May 12, 1932,. Serial No.-. 6 1-0 847 1 Gl'ai m :(Cl. zen-err This invention relates to certain new and use v Referring now more particularly to the aocom f ul improvements in carburetors and; refers more panyingdrawings, the numeral: 5 represents: the particularly to carburetors oi the type shown irrbody oi the carburetor having an air inlet dand: the co-pendingl, application of Warner E. Armanoutlet 'l connectable-withan engine manifoldr strong; Seriat No. 5891 116, filed January 27th, A, float chamber 8=is carried. by the body to con 1932. i trol the: admission of fuel-to the carburetor from i As described in: the cor-pending application, the a: feed line 9, and the float chamberis communi carburetor to which this invention appertains ca ted-througha=passage lwith1a fuel jet indi embodies a-ctuel: jet having a movable: element: catect generally by the numeral 11'. responsive tothe'fiowerair through the carbu The jet 11 ext nds pw ly n o a V nturi retor verituri within which: the jet is positioned, p nin 1 f rm d y tw p nta y ta to regulate the v l m yof flue} dischafgedi irom a-ble elements 13: which aremounted for simu1-- the jet, i V taneous rotationopposite directions between T-hedegreeot movement of the niovab lejet elethe f n s-mia Wai n sp v y of 1- merit and the consequent adjustment of the jet thgfiflrburewli body- 79 discharge area, beingresponsive to the now of ,T p c fi fionstmction (it the rotata l air through the venturi, is substantia1lycoordimen-ts 1 3 has no" bearing UD the present mated with: the operating conditions of the en vention and; ay ascelltatned y erence to girls, and thus" roughly follows with the adjust-- thcaforementioned pp t isnot d h w-- 23- ment of the throttle valve. However it has been v r h the pp end D fi the l s foundthat at times the'jet will remain ina lifted di p in fi constricted I the Ven u position for a slrortperiod after the throttle has op i g and Concentric therewith.

closed. g i The jet per se comprises a central stem or This results in fuel waste and poor idling", and standP -De 16 Open throughout" t entire length a5 it is. therefore; an" object oi, this invention to and provided at its lower end with a flange L7, a

provide means for positively controlling the movhexagonalpertion' 18,- anda threaded stem: 19?

able jet element from the throttle valve, to insure by which the jet is mounted in the discharge coordination therebetween. end of the passage 10.

A more specific object of this invention resides The extreme upper end of the central stem or 3 3 in the provision of a positively mechanical stop standpipe 16 has its inner peripheral edge champositively controlled from the throttle valve to fered to provide a valve seat 20. limit the lift of the movable jet element to a cer- Slidably telescoped over the stem 16, is an outtain distance at each degree of throttle opening. er sleeve or tube 21. The upper end of this sleeve With the above and other objects in view is closed by a concave wall 22 from the center J; which will appear as the description proceeds, of which an inner tubular stem 23 depends to be this invention resides in the novel construction, telescopingly received in the upper end portion of combination and arrangement of parts substanthe stem 16. 'tially as hereinafter described and more particu- At its upper end the inner stem 23 is taperinglarly defined by the appended claim, it being unly enlarged to afford a metering cone 24, the 40 derstood that such changes in the precise emmajor diameter of which is substantially equal 1 bodiment of the hereindisclosed invention may be to the inner diameter of the valve seat 20 so that made as come within the scope of the claim. when the sleeve 21 is in its normal lowermost In the accompanying drawings, one complete position, the stem 16 is closed except for a small example of the physical embodiment of this inidling orifice 25 in the center of the concave 43 5 vention is illustrated constructed according to the closure 22. The flow of fuel from the jet is thus best mode so far devised for the practical applirestricted to the volume which may pass through cation of the principles thereof, and in which: the orifice 25.

Figure l is a View partly in section and partly Being located in the throat of the venturi, the in elevation of a carburetor embodying this inouter sleeve 21 is subjected to the vacuum provention; ducing the flow of air therethrough, so that un- 9 Figure 2 is an enlarged view partly in section der certain conditions the sleeve 21 and the and partly in elevation taken through Figure 1 inner stem 23, which together form the movable on the plane of the line 2-2; and jet element, are lifted to uncover the outer open Figure 3 is an enlarged detail view illustrating end of the stand-pipe l6. Longitudinal slots 26 1 05 the parts in their positions of maximum opening. are cut into the opposite sides of the sleeve 21 to reduce the effective vacuum on the end of the sleeve and prevent a too rapid lifting of the jet element and the consequent increase in the fuel flow. The slots 26 also permit the air passing through the venturi to enter the space between the sleeve 21 and the stand-pipe 16 and emulisfy the fuel as it issues from the stand-pipe.

At the upper end of the sleeve 21, directly beneath the closure wall 22, is a plurality of discharge ports 2'? through which the air entering the space between the stand-pipe and the sleeve 21 and the fuel issuing from the uncovered open end of the standpipe, issues.

The area of the open end of the standpipe is determined by the degree of lift of the sleeve 21, through the metering cone 24 and as will be readily apparent, the maximum area of opening is obtained when the sleeve 21 is lifted to the position at which the lower small end of the metering cone aligns with the valve seat 20 at the open end of the standpipe. In lifting the sleeve 21, from its normal position, its weight must be overcome by the flow of air through the venturi, and to control further lifting of the sleeve, 2. series of weights in the form of inverted telescoped cups 28 are provided. These cups normally rest on the flange 17 and are successively picked up by the sleeve 21 as it is lifted in the manner described in detail in the aforementioned co-pend-- ing application.

As hereinbefore brought out it sometimes happens that the fiow of air through the venturi is sufficient to elevate the sleeve 21, even though the throttle is in its closed or partially closed position. This condition results in'fuel waste and is overcome in the present invention .by means of a stop pin 29. The pin 29 has its lower end positioned above the closure wall 22, but to one side so as not to obstruct the orifice 25, and has its upper end 30 linked to the shaft 31 of the throttle valve 32 in the outlet discharge '7. A guide 33 is suitably mounted from the body of the carburetor and has an elongated slot 34 within which an offset portion 35 of the stop pin is slidably mounted so that when the throttle shaft 31 is rotated in the customary manner to open and close the valve 32, the stop pin 29 will be raised and lowered.

In this manner, the possible lift of the sleeve 21 is at all times positively limited by the position of the throttle valve 32 so that the fuel discharge is positively and properly co-ordinated with the position of the throttle valve.

In Figure 1, the throttle valve is shown closed and the sleeve 21 of the jet in its lowermost position. In Figure 2, the throttle valve is partially open and the movable jet element likewise is in an intermediate position of elevation defined by the stop pin 29, and in Figure 3, the valve is shown in its fully open position with the jet sleeve 21 in its maximum position of elevation.

From the foregoing description, taken in connection with the accompanying drawings, it will be readily apparent to those skilled in the art to which an invention of this character appertains, that this invention affords a simple and efiicient means for positively co-ordinating the flow of fuel from the jet with the position of the throttle valve.

What I claim as my invention is:

In a carburetor, a fuel jet having a movable element to regulate the flow of fuel therefrom, said movable element responding to the flow of air through the carburetor to increase the fuel discharge from the jet, a throttle valve, a wire stop pin bent medially to provide upper and lower substantially vertical portions oifset with respect to each other and connected by a medial horizontal portion, means to freely pivotally mount the upper end of the stop pin from the throttle valve so that opening of the throttle valve lifts the stop pin, and a fixed guide having a vertical slot to receive the medial horizontal portion of the stop pin and hold the same during movement thereof in a position with the extremity of its lower portion in the path of movement of the jet element so that the degree of movement of the jet element in response to the flow of air through the carburetor is at all times limited by the position of the throttle valve.

WERNER E. ARMSTRONG. 

